File in Section:

Service Bulletin

-

Bulletin No.:

PIT5171C

Date:

May, 2013

PRELIMINARY INFORMATION
Subject:

Service Stability, Traction, ABS Rear Wheel Speed DTC Or Chassis Expansion And
High Speed Bus Communication Fault

Models:

2010 - 2013 Chevrolet Equinox
2010 - 2013 GMC Terrain
With Any Combination of DTCs U0073 U0074 U1826 U1827 U18A2 U0125 C0196 C0287
C0186 C056D C0045 C0050 Symptom 00 06 3B 4A 4B 5A 39 42 54 71

This PI was superseded to update recommendations and add photos. Please discard
PIT5171B.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern
Customers may comment on an intermittent DIC message Service Traction/Stability, ABS indicator or Service All
wheel Drive. Upon diagnostics the technician may find DTCs related to the chassis bus, or rear wheel speed sensor
with U0125 00 U0074 00 U0073 and or wheel speed sensor C0045 C0050 symptom 06 DTCs. Other DTC U0125
U0126 C0196 SYM 5A C0710 SYM 5A or no communication with (RDM) Rear Differential Module. This may be
related to an internal wire break inside the wire harness insulation to the X411 connecter due to rodents. (Location in
the left rear under the vehicle).

Recommendation/Instructions
Several conditions and symptoms have been found to be related to a wire harness at the left rear under vehicle.
Inspect the wire harness insulation within 1 inch of the X411 before and after connecter. It may be necessary to
remove the tape and conduit from the wire harness for inspection upstream from the X411 connecter. Some Issues
have been found with circuits 6105 and 6106 for chassis bus wires and serial enable circuit 5986 and 120 ohm
opens in 2500 and 2501 or 6106 and 6106. Other circuits 884, 885, 882, and 883 when related to rear wheel speed
sensor codes C0045 or C0050. During inspection you may notice chewed up conduit or a discoloration in insulation
in one spot of the wire. If you pull the wire near that area the insulation it will break exposing the broken wire and
possible corrosion or rodent damage. Repair the circuit to complete the procedure.
Diagnostic tips on intermittent Chassis Buss and High Speed LAN Buss: Find a known good vehicle and check the
ohms between 6 & 14 and 12 & 13 and voltage readings of each for comparison. Using DVOM set to Ohms, connect
meter between DLC pins 12 and 13 for chassis buss or 6 and 14 for high speed buss of DLC connecter, set the
meter to Min / Max, and wiggle the harness up and down under the left-rear areas of the connecter. When you hear
the meter beeping, check that area of the harness.

Note: Wire broken within the insulation has also been found high up in the harness X411 it will be necessary to
lower the harness to gain access. Reference the following photos:

2893988

2894019

3344376

3420854

Damaged conduit

3420856

Wires chewed through

Warranty Information
For wiring repairs covered under warranty, please refer to latest version of bulletin 10-00-89-005 for warranty
information on wire/connector repairs.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.